Here is Lucy Lawless: In her Starz adventure-action series she builds on worldwide fame as Xena, Warrior Princess, by playing wily Lucretia, widow of the Roman sports impresario whose “ludus” – an extreme training camp for gladiators – was where Spartacus had been enslaved. Transported from Capua in the first century B.C. to modern-day Manhattan, Lawless – in bright sweater and snug jeans – is pretty, girlish and full of laughs.

Alongside her for this recent interview is Liam McIntyre, who is taking over the role of Spartacus as the new season begins (Friday at 10 p.m. EST). His personality is far removed from the raging Thracian out to forge an army and topple the Roman Empire. Instead, McIntyre is chipper, affable and ready with wisecracks delivered, at times, in a comic squeal.

“More than all my dreams come true, in one fell swoop,” he declares, though now he’s not joking as he describes the thrill of landing this show’s title role. “It’s almost impossible to fathom.”

The first season concluded two years ago in a brutal rebellion led by Spartacus at the ludus. Roman blood flowed and his masters’ bodies dropped. Among the many victims were seemingly Lucretia.

Now the saga picks up just a few weeks later with the gladiators having made their escape and Spartacus plotting widespread payback to their oppressors. And during the hour, Lucretia makes her shocking return.

Watch The “Vengeance” Premiere Early:

“She’s lost everything,” says Lawless. “She’s lost her husband, her baby, her lover, the house, her status – and her marbles.”

“Spartacus: Vengeance” retains a potent mix of hyper-realism and epic fantasy, with generous helpings of graphic violence, orgiastic nudity, racy sex and other visual pizazz. It remains a hard-body romp on a CGI sprawl.

But real-life tragedy, too, is a part of the story.

Andy Whitfield, who originated the role of Spartacus, announced in March 2010 that he was stricken with non-Hodgkin Lymphoma. That May, a six-episode prequel concentrating on characters other than Spartacus was set for the following year, to give Whitfield time off for treatment. But a few months later when the cancer returned, he announced his departure from the show. Last September, he died at age 39.

“Being a fan of the show, I loved Andy’s Spartacus so much,” says McIntyre, now 29. “He wasn’t just an action hero. In my auditions I tried to capture the heart that I felt in Spartacus due to Andy’s great performance.”

“The show needed someone who could not only carry the role that Andy had created,” Lawless adds, “but also bring something of his own that was authentic. We didn’t want a knockoff.”

But McIntyre was hardly Spartacus-brawny when he got to the set in New Zealand for his audition.

“I’d never liked my body,” he confides, “and my nightmare was to be filmed in underwear.”

Hearing that, Lawless explodes with a laugh.

“I was no body builder,” he goes on. “I was just this guy who liked sports and video games.”

“He was level 76 on `World of Warcraft,’” Lawless cracks.

“You’re not as wrong as you want to be on that,” McIntyre fires back with a grin.

It took months of grueling training for McIntyre to bulk up to Spartacus proportions – “that kind of intense exercise is horrible,” he cringes – and only then, finally, to clench the role.

His selection to inherit Spartacus’ leather Speedo was announced last January.

The ailing Whitfield supported McIntyre as the recasting choice, and offered to meet with his successor, “which I thought was amazingly big-hearted considering everything he was going through.” Whitfield’s failing health prevented their getting together, “but we exchanged emails,” says McIntyre, “and I feel very blessed to have those.”

“It was a difficult way for you to start,” says Lawless.

“But what a privilege,” McIntyre replies, “to be given the honor of trying to continue that legacy.”

The Australian-born McIntyre, who made his U.S. television debut two years ago in HBO’s miniseries “The Pacific,” became an actor in an unlikely way: while studying business in Ireland on a student-exchange program. A chum inveigled him to take a role in a school production, and after first resisting, he got the bug.

“One day during a performance it all clicked,” says McIntyre. “And then, when `Gladiator’ came out, I wanted to be in a film like that more than anything. Now, here I am!”

When shooting on “Spartacus” began, McIntyre slipped into the routine with relative ease.

“Bringing Liam in was as easy a transition as it could be,” says Lawless, who had weathered the series’ uncertainty both as a principal player and as the wife of executive producer Rob Tapert. “Because of who Liam is, and because everybody else is so good at their jobs, it smoothed over the discombobulation that comes from having a star disappear from your roster.”

But that doesn’t mean Whitfield was forgotten, or that he isn’t missed as Spartacus fights on.

“This great journey that I get to go on now – there are times when I just get so sad `cause it seems so unfair that someone who had this exact experience a couple of years ago isn’t here to enjoy it now,” says McIntyre, his eyes damp in a way you wouldn’t associate with Spartacus. “It’s a shame.”

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